There are control devices that control access to storage devices such as hard disk drives (HDDs). Such a control device monitors access errors that occur when accessing the storage devices. When an access error occurs, the control device holds the error occurrence status as an error count based on the content of the error. If the error count reaches a certain value, the control device determines that the corresponding storage device has malfunctioned and addresses the problem, for example, by cutting off the storage device.
The following storage system has been proposed as an example of a storage system having a function of monitoring failures of storage devices. In this storage system, when a connection control unit that connects a communication control unit and a plurality of storage devices finds a failure in accessing one of the storage devices, the connection control unit transmits an error report to the communication control unit. On the basis of the error report, the communication control unit determines whether to perform failure recovery processing.
In addition, for example, the following disk array has also been proposed. In this proposal, each of the disk devices constituting the disk array collects and holds its own operation history information and forwards this operation history information to a higher-level control device in response to a forwarding request therefrom.
See, for example, the following documents:
Japanese Laid-open Patent Publication No. 2007-141185
Japanese Laid-open Patent Publication No. 6-51915
As recent storage systems include more control devices that control access to storage devices, the scale of an individual storage system is increasing. In addition, the increase of the scale has created demands for more diversified access paths and access control systems. For example, there has been considered a technique for allowing a control device to access a storage device via another control device. However, with such a configuration, an error caused by accessing a single storage device could be detected by a plurality of control devices. If each of the control devices individually determines failures of storage devices, a failure per storage device cannot be adequately detected.